Reuters latest
Doubts over lightning's role in missing jetliner
Brazil said Monday's aircraft last made radar contact at 0133 GMT after passing the Fernando de Noronha islands off its northern coast, about 250 miles (400 km) south of the equator.
It was heading towards a notorious stormy patch that shifts around the equator known as the Intertropical Convergence Zone.
It had been preceded safely on the same track 30 minutes earlier by a Boeing 747-400 heading to Frankfurt for Lufthansa, according to a source with access to data transmitted from jetliners for the World Meteorological Organisation.
Two hours later an MD-11 cargo plane also flown by Lufthansa passed just south of the same spot on the way to West Africa, the source told Reuters, asking not to be identified.
Neither aircraft reported any anomaly.
"You can't tie it down to lightning with the information we have; for me it's a red herring," said the source, who specialises in aviation weather. Lufthansa declined comment.
CIRCUIT FAILURE
An Air France captain operating on long-range routes, who agreed to speak to Reuters on condition of anonymity, said lightning alone was unlikely to have caused the presumed crash.
"I would not think it was possible that lightning could lead to a short-circuit and disrupt all of the plane's electrical systems. Test planes have resisted some 30 lightning strikes and nothing ever happened," the pilot said.
More likely, he said, is that the jet might have suffered an electrical system failure which would have turned off its radars and communications systems, turning it blind and making it more vulnerable to storms and strong lateral air currents.